NASA has captured detailed observations of interstellar object 3I/ATLAS, a visitor from beyond our Solar System that has sparked both excitement and speculation. Discovered on 1 July 2025 by the ATLAS survey in Chile, the comet is the third confirmed interstellar object, following 1I/ʻOumuamua (2017) and 2I/Borisov (2019). Moving on a hyperbolic trajectory, 3I/ATLAS entered the inner Solar System at high speed and will pass safely, never coming closer than 1.8 AU to Earth. While some commentators, including astrophysicist Avi Loeb, have speculated it could be an alien spacecraft or nuclear-powered object, NASA and other scientific teams confirm that all current data indicate a natural comet, rich in CO₂ and water ice, with a nucleus likely smaller than 1 km.

NASA’s telescopes reveal comet composition

NASA’s James Webb Space Telescope (JWST) used its Near-Infrared Spectrograph (NIRSpec) to analyse the comet’s molecular composition, detecting water ice, carbon monoxide, and unusually high levels of carbon dioxide. These observations, supported by SPHEREx and Hubble Space Telescope data, show the coma and dust tail are generated by natural outgassing rather than artificial sources. The high CO₂ content makes the comet unusually bright, a factor that may have contributed to speculation about its “unexplained glow.”

Debunking alien and nuclear claims

While theories about alien spacecraft or nuclear-powered objects have circulated in public commentary, the scientific consensus is clear: 3I/ATLAS is a natural interstellar comet. Its hyperbolic trajectory, coma formation, and chemical composition match known processes of icy comets ejected from other star systems. NASA, ESA, and multiple observatories emphasise that no evidence supports extraterrestrial or artificial origins, with ongoing observations focused purely on understanding the comet’s structure, activity, and insights into planetary formation beyond our Solar System.